Update yajl to 2.1.0

2.1.0
* @nonodename, @patperry - fixed some compiler warnings
* @yep, @emaste - documentation improvements
* @sgravrock - build fix for NetBSD (and whenever sh != bash)
* @rotty, @brimstone3, @lloyd - allow client to reset generator
* @sgravrock - remove bash dependencies
* @lloyd - add api tests
* @rflynn - remove ruby dependency
* @cloderic - nmake install works on windows
* @shahbag - build fix for qnx
* @breese - debugging improvements
* @lloyd - json_verify supports -s flag for stream processing
* @lloyd - json_reformat supports -s flag for stream processing

2.0.4
* @jcekstrom - additional checking in integer parsing
* @jcekstrom - fix a bug in yajl_tree that would cause valid json
integersto fail to parse
* @plaguemorin - fix a memory leak in yajl_tree (error strings were
being leaked)
* @7AC - reset errno
* @ConradIrwin - include flags to reformatter to allow toggling of
escape solidus option

2.0.3
* John Stamp generation of a pkgconfig file at build time.
* @robzuber bugfix in yajl_tree_get()
* @lloyd - fix for compilation on 64 bit windows

2.0.2
* lth fix typos in yajl_tree.h macros YAJL_IS_INTEGER and
YAJL_IS_DOUBLE,
contributed by Artem S Vybornov.
* lth add #ifdef __cplusplus wrappers to yajl_tree to allow proper
usage from many populer C++ compilers.